Spillway gates of the Kaptai Dam in Rangamati have been opened to reduce pressure in the Kaptai Lake, one of Southeast Asia’s largest man-made reservoirs. According to the Karnafuli Hydroelectric Power Station, all spillway gates of the dam were opened at 12:10 am on Tuesday, August 5.

Mahmud Hasan, Superintending Engineer and Manager of the Karnafuli Hydroelectric Power Station, told Bonik Barta that due to the rising water pressure in the lake, all 16 spillway gates have been opened by 6 inches each. As a result, 9,000 cusecs of water are being released per second into the Karnafuli River through the spillways.

According to the control room at the power station, around 32,000 cusecs of water are also being discharged through five operational power-generating units. Combined, the total discharge into the Karnafuli River currently stands at 41,000 cusecs. The water eventually flows into the Bay of Bengal.

Meanwhile, ahead of the water release, social media platforms, especially Facebook, saw rising public concern. Despite being a routine annual occurrence, this year’s spillway opening triggered heightened anxiety among locals, according to observers. Both the Rangamati district administration and Kaptai dam authorities have urged people not to panic but to remain alert.

On Monday afternoon, the Karnafuli Hydroelectric Power Station issued a special announcement stating that the gates could be opened at any time and requested residents along the riverbanks to stay alert without fear.

Later that night, the Nezarat Deputy Collector (NDC) of Rangamati confirmed via a public message that the spillway gates would be opened between midnight and 1 am. Locals along the Karnafuli River were once again urged to exercise caution.

Speaking to Bonik Barta, Rangamati-based community organizer Saikat Ranjan Chowdhury said, “Almost every year, when water levels in the Kaptai Lake approach or reach the danger mark, the spillway gates are opened to release water into the Karnafuli River. The water eventually flows out to sea. But in recent years, we’ve seen unnecessary panic surrounding this normal procedure. In reality, when water is released, the volume is gradually increased depending on pressure. Currently, 9,000 cusecs are being discharged through the spillways, while power generation is releasing around 32,000 cusecs. In fact, much more water is released through power production than through the spillways.”

He added, “Every year, the water level in the lake rises, and as a result, even the iconic hanging bridge at Rangamati’s tourist site gets submerged. When the water recedes, it resurfaces. Those who have built illegal settlements in low-lying areas of the lake face problems when water levels rise. Some try to frame this as a flood or inundation. But in reality, water hasn’t approached people—people have moved closer to the water. That might be the root of the panic we’re seeing.”

Kaptai Lake was created in the 1960s when the then-Pakistani government built a dam across the Karnafuli River in Kaptai, part of what was then the Chittagong Hill Tracts. The 725-square-kilometer lake submerged vast tracts of land, forests, and homes, displacing thousands of indigenous residents.

Initially, the Karnaphuli power station had a generation capacity of 80 megawatts. Over time, this was gradually increased to 230 megawatts by the government of Bangladesh. When all five units operate at full capacity, the average cost of power generation is about BDT 0.40 per megawatt—making it the most cost-effective among all thermal, coal, and gas-fired power plants in the country. This is why the Bangladesh Power Development Board (BPDB) prioritizes maximizing electricity generation from the Kaptai Lake throughout the year by maintaining an adequate water level.